[ effect of arsenic trioxide treatment on mitochondrial apoptotic gene expression in acute promyelocytic leukemia cell line]

Acute promyelocytic leukemia [APL] is one of the most malignant forms of acute leukemia with a fatal course of only weeks which represents 10-15% of AML in adults. Arsenic trioxide as a single agent factor [without chemotherapy] is the treatment of choice for APL patients; it induces cell death through apoptosis but the mechanism by which arsenic targets apoptosis and dramatically affects gene expression remains poorly understood. Since arsenic is used as first line treatment in Iran, it is worth investigating its effect on expression of genes involved in APL. In this descriptive study, to understand the underlying mechanisms of cell death induction by arsenic, we treated NB4 cell line in a dose and time dependent manner. Extracting RNA and synthesis of cDNA, gene expression of apoptotic genes in mitochondrial pathway including caspase3, Mcl-1 and Bcl-2 was analyzed through Real-Time PCR. Our findings showed that As[2]O[3]-induced cell death was paralleled by reduced expression of the antiapoptotic protein Bcl-2 but the expression of Caspase3 and Mcl-1 did not change after arsenic treatment. These results suggest that changes in Bcl-2 gene expression may be one of the mechanisms of action of arsenic in induction of apoptosis, while Caspase3 and Mcl-1 gene expression are not affected by arsenic at the transcriptional level

effects of arsenic trioxide and zoledronic acid on malignant plasma cells derived from bone marrow cells of multiple myeloma patients

Multiple myeloma [MM] is a disease of plasma cells that has fatal consequences. New agents associated with molecular targets have prompted clinical investigators to design new treatment strategies initially for advanced MM and later for newly diagnosed MM, with encouraging preliminary results. We devised a project to assess the mechanisms of action of two drugs, Arsenic trioxide [ATO] and Zoledronic acid [Zometa] on Bone marrow mononuclear cells [BMMCs] derived from patients. Bone marrow samples were collected from 10 patients after receipt of formal consent. BMMCs were collected from samples. In two parallel sets of experiments, BMMCs were treated with 0.5, 2, 6 micro M ATO and 0.1, 10, 100 micro M Zometa, for 72 h. The following analyses were then performed on treated cells as compared to untreated cells [assumed as control]: cytotoxicity using Micro culture tetrazolium test [MTT assay]; matrix metalloproteinase-2 zymography; comparative gene expression analysis of IL-6, vascular endothelial growth factor [VEGF] and intercellular adhesion molecule-1 [ICAM-l]. MTT assay showed significant proliferation inhibition in ATO high dose treatment [6 uM]. However, no significant inhibitory effect of Zometa was seen. Zymography analyses showed significant decrease in gelatinolytic activity in treated cells. Analyses of gene expression using Real-Time RT-PCR methodology showed significant decrease in IL-6, ICAM-1, and VEGF genes as normalized against Hypoxanthine phosphoribosyltransferase normalizer and as compared with untreated cells. Both ATO and Zometa could significantly decrease MM cells critical phenotype and genotype. This finding could support the hypothesis that ATO or Zometa could inhibit growth and metastasis of malignant cells